Coupling of solar photoelectro-Fenton with a BDD anode and solar heterogeneous photocatalysis for the mineralization of the herbicide atrazine

详细信息    查看全文

• 作者：Benjam铆n R. Garza-Campos ; Jorge Luis Guzm谩n-Mar ; Laura Hinojosa Reyes ; Enric Brillas ; Aracely Hern谩ndez-Ram铆rez ; Edgar J. Ruiz-Ruiz
• 关键词：Anodic oxidation ; Atrazine ; Solar heterogeneous photocatalysis ; Solar photoelectro-Fenton
• 刊名：Chemosphere
• 出版年：February, 2014
• 年：2014
• 卷：97
• 期：Complete
• 页码：26-33
• 全文大小：1340 K

文摘

Here, the synergetic effect of coupling solar photoelectro-Fenton (SPEF) and solar heterogeneous photocatalysis (SPC) on the mineralization of 200 mL of a 20 mg L<sup>鈭?sup> atrazine solution, prepared from the commercial herbicide Gesaprim, at pH 3.0 was studied. Uniform, homogeneous and adherent anatase-TiO<sub>2sub> films onto glass spheres of 5 mm diameter were prepared by the sol-gel dip-coating method and used as catalyst for SPC. However, this procedure yielded a poor removal of the substrate because of the low oxidation ability of positive holes and <sup>sup>OH formed at the catalyst surface to destroy it. Atrazine decay was improved using anodic oxidation (AO), electro-Fenton (EF), SPEF and coupled SPEF-SPC at 100 mA. The electrolytic cell contained a boron-doped diamond (BDD) anode and H<sub>2sub>O<sub>2sub> was generated at a BDD cathode fed with an air flow. The removal and mineralization of atrazine increased when more oxidizing agents were generated in the sequence AO < EF < SPEF < coupled SPEF-SPC. Organics were destroyed by <sup>sup>OH formed from water oxidation at the BDD anode in AO, along with <sup>sup>OH formed from Fenton鈥檚 reaction between added Fe<sup>2+sup> and generated H<sub>2sub>O<sub>2sub> in EF. In SPEF, solar radiation produced higher amounts of <sup>sup>OH induced from the photolysis of Fe(III) species and photodecomposed intermediates like Fe(III)-carboxylate complexes. The synergistic action of sunlight in the most potent coupled SPEF-SPC was ascribed to the additional quick removal of several intermediates with the oxidizing agents formed at the TiO<sub>2sub> surface. After 300 min of this treatment, 80% mineralization, 9% mineralization current efficiency and 1.93 kW h g<sup>鈭?sup> TOC energy cost were obtained. The mineralization of atrazine was inhibited by the production of cyanuric acid, which was the main byproduct detected at the end of the coupled SPEF-SPC process.